Manufacture of oxalate



H. W. PAULUS. MANUFACTURE OF- OXALATE.

APPLICATION FILED JULY 26, 1920. j I 'PatentedJune 20, 1922, I

HERMAN PAULUS,.6F RICHMOND HILL,

"re i NEW YORK, AS SIGNOR TO ROYAL BAKING POWDER COMPANY, A CORPORATION OF NEW JERSEY.

a citizen of the United States, and a resident of Richmond Hill, Long Island, in the county of Queens and State of New York,

have invented certain new and useful lmprovements in the Manufacture of Oxalate, of which the'following is a specification.

The invention relates to the. manufacture .of ox alates. r

The object of the invention is to increase "the percentage 'of production of oxalate from a given amount of formate and at the same time decrease the cost-of "manufacture; With this object in View, the in'-' vention consists in manufacturing oxalate from finely divided dry formate', which is subjected to the requisite heat to convert it into oxalate by dropping it through a descending Vertical column of heated gases. For the purpose of illustrating'the princi: ples of the invention, the manufacture 0fsodium oxalate will be specifically described. It will be understood, however, that the in-- vention is not to be restricted to the manu-' facture of sodium oxalate, inasmuch-as the particularly the-alkaline oxalates, are within the purview of the -invention? The process'of theinvent on may.be per formed in any usual or-preferred form .of

' apparatus. #In the accompanying drawing' is illustrated diagrammatically -;;a series ,of

apparatus 'orjreceptaclesi operatively conf nected together and sealed against the atmosphere suitable for the practice of the process.

The preliminary process-of making the sodium formate consists in subjectinga solu tion ofthe metal hydroxideto the carbon monoxide gas at the requisite. temperature.

, andpressure to convert the hydroxidesoluz I through a heatd'zone inaccordance with the principles of the invention toc'onvertthe tion into a. formate solution 'and then evaporating the formate] The'evaporated formate in a finely divided state is'fthen lpassed formate into oxalate The caustic soda solution-utilizedfor the] I tanks 7, 16 and 21, carbon monoxldeis caused raised from the tank 1 by'a pump 3 into a" preheating tdrum andsteam condensers with which asteam trap '5 is connected.

7,1 6 a 21 'is provided with a 26 andfal thermometer 27.

MANUFACTURE OF OXALATE.

Specification of Letters Patent. Patented June 20);

1920. Serial No. 399,086.

From the preheating drum and steam condenser 4 the solution passes by gravity through a pipe 6into an upright receptacle or tank 7 inthe lower end of which is placed a steam coil 8 for'supplying suflicient heat to begin the desired chemical reaction. Inasmuch as the reaction of the carbon monoxide with'the caustic soda is exothermic, the supply of steam maybe shut off after the process is fairly under way. The solution flows from the tank 7 through the pipe9 in- 'to' a. centrifugal pump 10 which it is raised through the pipe 11 having the two branches -12 and-'13 at its upperend. By

adjusting the valves 14 and.15 located in'the branch pipes 12 and 13, respectively, the amount; of solution which passes through them may be-regulated. It is desirable that the greater portion of the solution passing up through the pipe 11 be returned-to the a tank '7" for further reaction with'the carbon monoxide and that only a small portionof V v the solution pass from the pipe 11 into the" f second tank or receptacle 16. The. solution enters the tanks 7 and 1 6 .in finelysub- I I divided or spray-like condition. production of all kinds of oxalates, and

The solution which enters the tank 16 valves;24;and 25 located respectively in the branchfpipes 22 and23 are so adjusted. that tof thetank-16 and only a small portion of thesolutioil lispermitted to enter theitank '2 In thebottom'of the tank 16'is placed the greater-part of the solution is returned";

ain coil l'7 lwhich is-used for the same "u 'ose, asthe steam coil 8 infthe tank 7. i

liile" the c'au'stic soda solution is passing .thfoQ gh-"lihe'ianks and 16 it is converted."

into sodiumrjformate as will moreclearly ap:

pear below arid-the sodiumformate solutionv formedeis evaporated and thoroughly th s drie in: the tank 21. Each of the tanks safety valve iWhile the solution, first inthe forniof caustic soda and then in' the form of-sodium formats; is passing sequentially through the to, tranvel through.v the tanks; in the reversg direction, namely, first through the tank 21, then through the-tank 16 and finally through the. tank (7.; The first action of the slot carbon monoxide gas passes through a pipe 32 having a check valve 33 into the lower end 'of the third or formate tank 21. As the hot gas rises in the tank 21 it intimately mingles with the particles of sodium formate fall- 'ing through the tank from the branch pipe 22 and thoroughly dries them. This action reduces the temperature of the carbon mon-' oxide so that it enters the tank 16 through the connecting pipe 34. at substantially 175 C. This temperature is sufficient forconverting the caustic soda into sodium formate.

From the tank-16 the carbon monoxide passes through the connecting pipe 35 into the tank 7 and from the tank 7 the residue gases, namely, the nitrogen and the hydrogen accompanyin the carbon monoxide, pass through the plpe 36 into the preheating drum and steam condenser 4. These gases are saturated with steam which" has been takenup by evaporating the sodium formate in the tank 21 and by passing through the caustic soda and sodium formate solutions 1 in'the-tank's l6 and 7. Inthe steam con-f denser 4 thesteam is condensed and carried off through thetrap 5. The ases freed from the steam pass through t e pipe 37 into thesuperheater 38. The finely divided sodium 'formate falling into .the bottom of the tank 21-is kept in its ,powderedcondition by ,a-stirrer or agitator. 40 driven by the .gears41.

a v through a pipe 42.into anoxalate converter- Th powdered formateil is J'introduced or-retort 43 where it is converted into oxalate, 1 Theupperend of the converter 43 is I l provided with a jacket 44 for the .admission of the hot gases'by which the formate is converted into oxalate.v The jacket 44 opens into the retort' through a series of holes 45.

-. The. heating medium for converting the formate 'into'oxalate consists of gases supplied from" the superheater 38. whence they pass through the pipev 46 into the jacket 44 and from there through the] holes 45 into the interior of the retort. It is well known that formate converts into oxalate at a temperature ranging from 360 C. to 440 C. and that under certain conditions, below and above these temperatures it converts into carbonates Consequently it is necessary to raise the formate from a temperature-of about 200 C'., atwhich the formate is stable,

to at least 360 C. as quickly as possible in order-"to prevent it from converting into carbonate. The present process effectively prevents the formation of carbonate. Inasmuch as the sodium formate is in. a finely divided state it offers a relatively large surface to the action of the hot gases and is thereby instantly fconverted into sodium oxalate, the conversion eflicienoy being'fully 98%. The powdered oxalate falls to, the bottom of theretort whence it is conducted by the rotating valve 47,

'The hot gases from the converter or retort 43, now enriched by the hydrogen given off by th. formate' in converting into oxalate, pass through. .a pipe 48 into the dust collector 49 for the elimination of fine particles of oxalate therefrom.. From ,thedustcollector 49 the gases pass through the discharge pipe 50 into'awater seal 51 and thence throughthe pipes53 and 54 into the 'superheaters 30 and 38 where they are utilized for heating purposes. A' second water seat 52 is provided which acts'as an auto- 111131713 relief in case the valves 55 and 56 are c ose It will be observed that when finely j divided dry formate is introduced into the top 'of'the descending vertical column-of inert gases which are maintained in the retort 43 at a temperature ranging from 360 C. to 440 0., the particles of formate remain in suspension in the heated gases an appreciable length of time. The minuteness of the particles is such that the periodof suspension is amply sufiicient for substantially complete conversion into oxalate. This will be unvderstood when it is considered that each particle-is' entirely surrounded by the. heated gas. It will thus beseen that the conversion of the formate particles into oxalate must take place readily, and that the efiicienc of con-' version must be relatively high. 0 far as I known, the conversion of formate into oxalate has heretofore involved treat ng the formate 'inmass, and never as separate particles, separated from each other by an a-ppreciable'amount of converting gas. In this connection it will be borne in mmd that the heat conductivity of theformate particles is veryv low and consequently the heat is by transmission.

conveved to them better by convection than Having thus pointed out the principles of I the invention and illustrated and describedan apparatus in which the invention may be practiced, what is claimed as new is:

1. 'The process of making oxalate from finelydivided dry formate which consists in .maintaining a descending Verticalcolumn of inert {gases at a temperature ranging from 2 360 C. to 440; (1., and dropping the finely divided formate into the column of heated gases.

2. The process of making oxalate from finely divided dry formate which consists in maintaining a descending vertical column of inert gases at a temperature ranging from 360 C. to 440 C. and suspending the finely divided formats in the column of heated gases until it is converted into oxalate.

3. The process of making oxalate from formate which consists in maintaining inert gases at a temperature ranging from 360 G.

to 440 C. and dropping finely-divided formate into the heated gases.

4. The process of making oxalate from formate which consists, in maintaining a descending column of finely divided dry formate and surrounding the particles of formate With gases heated to' a temperature ranging from 360 C. to 440 C.

HERMAN W. PAULUS. 

